问题
不定项选择题
鉴别下列各组物质，所用试剂不正确的是[ ]
待鉴别的物质 | 鉴别试剂 | |
| A. | 稀盐酸和氢氧化钠溶液 | 无色酚酞试液 |
| B. | 海水和蒸馏水 | 硝酸银溶液 |
| C. | 铜和黄金 | 稀盐酸 |
| D. | 氧气和二氧化碳 | 燃着的木条 |
答案
答案：C
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鉴别下列各组物质，所用试剂不正确的是[ ]
待鉴别的物质 | 鉴别试剂 | |
| A. | 稀盐酸和氢氧化钠溶液 | 无色酚酞试液 |
| B. | 海水和蒸馏水 | 硝酸银溶液 |
| C. | 铜和黄金 | 稀盐酸 |
| D. | 氧气和二氧化碳 | 燃着的木条 |
答案：C
| 完型填空。 | ||||
| For long, a little boy was wondering why his deskmate could rank 1st in the class whenever he wanted to, while he himself failed to: he only ranked 21st. At home, he asked his Mom, "Mom, am I more 1 than others? I feel I am obedient and as careful as him, but 2 I always fall behind?" Hearing the words, Mom was aware that her son began to 3 the sense of self- respect, which was now being injured by the ranking system. 4 at him, she went wordless, not knowing 5 to explain. In another test, the son ranked 17th, while his deskmate remained 1st. Back home he 6 the same question. Mom really wanted to inform his son that 7 differs, which means that students ranking 1st are supposed to be cleverer than normal ones. 8 , was this discouraging answer the one that her son was constantly 9 about? Thank goodness she did not open her mouth. How to answer her son's question? There were times when she felt an urge to say, "You are too lazy. You are not as hard-working as others…" but she stopped 10 imagining her son suffering from the pains of unsatisfied grades and rankings. She thought it 11 to put any additional burden on his son and was trying to find out a perfect answer. Time passing swiftly, the son 12 primary school. Despite studying harder and better, he was still unable to keep up with his deskmate. To show her pride of him, mom decided to 13 him to the sea. During the trip, she managed to give an answer. Now, the son no longer worries about his 14 , and there are no boring guys who would inquire his grades in primary school, because, 15 the 1st ranking, he is admitted to Tsinghua University. Back home in winter vacation, he was invited to 16 the students and parents in his high school, In the speech, he mentioned a valuable experience in his childhood,"…When my mother and I were lying on the 17 , she pointed to the front and said, "Do you see the seabirds struggling for food over there? When the waves come near, little birds can rise 18 while awkward seagulls would take more time to complete the process. However, have you noticed birds that finally fly 19 the endless ocean are none other than the awkward seagulls?" The speech 20 many mothers present to tears, including his mother. | ||||
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